Door operators



A. M. BUEHLER DOOR OPERATORS June 25, 1968 Filed Feb. 7, 1966 INVEN'IOR. ALLAN M. BUEHLER 7Zm1w z/@ ATTORNEYS United States ABSTRACT 8F THE DISCLQSURE This invention provides an operator for a two-piece garage or the like door which is characterized by a transverse shaft across the top of the doorway opening, a link member fixed at its upper end to the shaft and at its lower end to the top section of the door and a lever arm connected to the shaft at one side of the doorway opening in such a way that the door can be opened by swinging the lever arm; the arrangement also including a reversible electric motor for swinging the lever arm and a safety device for interrupting current to the electric motor should something interfere with the opening or closing of the door.

This invention relates to the manufacture of garage doors and is particularly concerned with a garage door operator adapted for use with a door of the bifold type.

The term bifold is commonly used to describe that type of garage door which consists of two panels connected together by a horizontal hinge with the uppermost panel being pivoted to the door frame above the doorway opening. The operator of this invention is particularly adapted to use with a bifold door and to this end its main function is to swing the top panel up and down, with the lower panel following the upper in the normal fashion.

As is well known to those engaged in the manufacture and sale of garage doors, the term operator refers to a power-drive unit for opening and closing a door. Various arrangements are provided for setting such operators in motion. These include remote control devices wherein the opening and closing actions are initiated by radio transmitters or ultrasonic wave units. More commonly, the starting system may consist of simple switch devices which are attached directly to the garage door frame or positioned at a point remote from the garage, usually at some point on the driveway. The operator of this invention is adapted to use with any of the known control arrangements.

The chief difiiculty with operators known heretofore is that they are not adapted to use with bifold doors. For the most part, the known operators have been used with the common type of sectional door which rolls up in the manner of a roll-top desk so that the operator has essentially consisted of a power mechanism for exerting an upward pull or downward push on the door. Alternatively, the known operators have been adapted to open one-piece doors but in this case as well, the opening action has been one that exerts an upward pull on the door.

It is, therefore, an object of this invention to provide an operator which is particularly adapted to use with bifold doors.

It is a more specific object of the invention to provide an operator which is adapted to impart an upward or downward swinging movement to the top panel of a bifold door.

It is a further and related object of the invention to provide an operator for a bifold door which avoids difliculties which might arise due to jamming of the door when it is being opened or closed.

atent The above objects of the invention are achieved through the provision of an operator comprising a shaft mounted for rotation above and to the inside of the doorway opening, a link member fixed at its upper end to said shaft and pivotally fixed at its lower end to the uppermost door panel, means for rotating said shaft as to swing said link member upwardly and downwardly to open and close the door respectively, said shaft rotating means including a lever arm having one end freely mounted on said shaft for rotation relative thereto at one side of the doorway opening, a bracket member fixed to the shaft and having a base plate and a pair of opposed side flanges, said lever arm extending through said bracket between said side flanges, a limit switch fixed to the inside of each of said flanges and adapted to be tripped by said lever arm, a pair of springs positioned between said lever arm and said side flanges, said springs having sufficient bias to transmit a swinging movement of the lever arm to either one of said side flanges as to cause the bracket to swing, thereby rotating said shaft until a jamming action interferes with the opening or closing of the door, whereupon the bias of one of the springs is overcome as to permit said lever arm to move towards the associated side flange a sufiicient degree to trip one of said limit switches; said shaft rotating means further including a reversible electric motor having an operating circuit which includes said limit switches and being fixed to the door frame on the same side of the doorway opening as said lever arm, a screw fixed to and axially aligned with the output shaft of the motor, a screw follower carried on the screw, said follower being pivotally fixed to the other end of said lever arm whereby operation of said motor causes said screw to rotate, thereby moving said follower away from and towards the motor and carrying said other end of the lever arm therewith.

The invention will be more thoroughly understood from the following description of a preferred embodiment thereof as read in conjunction with the accompanying drawings.

In the drawings,

FIG. 1 is a perspective view of a bifold door having an operator in accord with this preferred embodiment of the invention installed thereon; and

FIG. 2 is a side elevation view of the upper part of the doorway shown in FIG. 1 as to illustrate the raised position of the door.

Referring to FIG. 1, the door illustrated is of the bifold type essentially consisting of an upper panel 10 and a lower panel 12, which are interconnected by a horizontal hinge 14. The upper panel is hinged to the door frame above the doorway opening. For a detailed description of one form of bifold door, reference may be had to United States application Patent No. 3,212,560, issued Oct. 19, 1965. In this particular case, the top panel is not hinged directly to the doorway frame but is carried on a pair of pin members 16 projecting inwardly from corner brackets 18, with the latter being attached to the door frame. In the case of the particular door illustrated, the corner brackets 13 carry an arrangement of pulleys and cables whereby the door may be counterbalanced by a counterweight received within a channel member 19 at one side of the door. However, it is to be understood that the operator of this invention is equally adapted to use with any type of bifold door, i.e. any door which is characterized by upper and lower panels connected together along a horizontal hinge line and having the top edge of the upper panel pivotally mounted above the doorway opening.

The operator of this invention essentially consists of a shaft 20, a lever arm 22, means for swinging the lever arm up and down, and a pair of link members 26 and 28 which are connected to the shaft 20 at their upper ends and are pivotally fixed to the top panel of the door at their lower ends.

Shaft 20 is carried by the corner brackets 18 in a pair of suitable bearings 3t While in the preferred embodiment illustrated in the drawings the shaft 20 extends across the full width of the door, it will be understood that the shaft may be shorter than this and may be connected to the top panel 10 by only one link member. In other words, the shaft and link member arrangement illustrated is a preferred means for transmitting the upward and downward swinging movement of lever arm 22 to the top panel.

In the case illustrated, the link members 26 and 28 are fixed to the shaft by having the latter received in collars 32 which carry tightening screws 34. This attachment of the link members to the shaft is a rigid connection so that rotation of the shaft causes swinging movements of the link members. The lower ends of the link members are preferably fixed to the top panel 10 through a pair of short links 36 which, in turn, are pivotally connected to brackets 38 fixed to the door. The purpose of the extra links 36 is to space the outer ends of the link members 26 and 28 from the top panel approximately the same distance as the shaft is spaced from the top frame member of the doorway. The effect of this arrangement is to provide a parellel linkage arrangement as to permit swinging movement of the top panel without danger of jamming within the system as would occur if the lower ends of the link members were attached directly to the door.

As can be readily appreciated from the drawings, the swinging of the lever arm 22 is accomplished by rotation of the screw 24 by the electric motor 40 as to cause the follower 42 to ride up and down on the screw. The lower end of the lever arm 22 is pivotally connected to the fol lower, preferably by means of the fork arrangement il lustrated.

While a rigid connection between the upper end of lever arm 22 to shaft 20 would accomplish the desired rotation of the shaft, the operator of the invention includes a safety device 4 for transposing the swinging movements of the lever Iarm into rotation of the shaft. The purpose of this safety device is to provide an automatic means for interrupting current to the motor should the door somehow become jammed during raising or lowering. This safety device consists of a bracket which is rigidly fixed to the shaft by a locking screw 46. It essentially consists of a base plate 48 having a pair of side flanges 50 and 52. The lever arm 22 is free to swing back and forth between the side flanges against the bias of the two springs 54 and 56 which are held in position by a transverse rod member 58. A pair of limit switches 69 and 62 are positioned within the safety device in such manner that they are contacted by the lever arm as the latter swings back and forth within the device.

In the normal course, i.e. when opening and closing of the door is effected smoothly without jamming, the lever arm 22, as it bears against the springs 54 and 56, will cause a swinging action on the safety device 44 as to rotate the shaft 20 in the desired manner. To this end, the springs are fairly stiff so that their bias is not overcome until the door is jammed. In this regard, it will be understood that the illustrated door has proved to be a smooth operating unit and is not expected to jam due to a failure within the door itself but only due to some external force including the possibility of a vehicle becoming stalled within the doorway with the door in the course of a closing operation. When the closing or opening of the door is interrupted, the bias of either one of the springs 54 or 56 is overcome and the lever arm swings within the safety device to a sufficient degree to trip either one of the switches 69 Dr 62 These switches are preferably of the type which will not only interrupt the current flow to motor 40 but which will automatically change the circuit operating the motor so that when the motor is next set in motion, it will operate in the reverse direction. Thus, for example, should some jamming action interfere with the closing of the door, a subsequent tripping of the master switch will cause the motor 40 to rotate in the direction which will cause the door to open.

Included in the type of jamming actions which might interfere with the action of the operator are the two limit positions of the door, i.e. the fully closed or fully open positions. The fully open position of the door is illustrated in FIG. 2. Here it can be seen that as the door reaches the fully open position, the bias of spring 56 is overcome and the switch 62 is triggered by the lever arm 22. Thus, when the motor is next started, it will rotate in that direction which will draw the follower 42 towards the motor as to swing lever arm 22 downwardly, whereby the door is closed. By the same token, a smiliar action takes place when the door is moved into the fully closed position so that when the motor is next started it will rotate in that direction which will drive the follower 42 away from the motor as to swing lever arm 22 upwardly. This motion is transmitted through the safety device and through shaft 20 and link members 26 and 23 to the top panel whereby the latter is also swung upwardly thereby opening the door.

As previously mentioned, the operator of this invention is adapted to use with any type of electrical circuit including the type of circuit which is operated by a radio transmitter carried in the vehicle stored in the garage involved. Alternatively, the master switch may be manually triggered and may be positioned at a point remote from the doorway or at the doorway itself. In this regard, it will also be appreciated that while reference has been made to garage doors throughout the specification, the operator is equally adapted to installation on bifold doors used for other purposes.

What I claim as my invention is:

1. An operator adapted for use with a bifold door of the type which is characterized by a pair of door panels hinged together along a horizontal hinge line with the uppermost panel being hinged to the door frame above the doorway opening, said operator comprising a shaft mounted for rotation above and to the inside of the doorway opening, a link member fixed at its upper end to said shaft and pivotally fixed at its lower end to the uppermost door panel, means for rotating said shaft as to swing said link member upwardly and downwardly to open and close the door respectively, said shaft rotating means including a lever arm having one end freely mounted on said shaft for rotation relative thereto at one side of the doorway opening, a bracket member fixed to the shaft and having a base plate and a pair of opposed side flanges, said lever arm extending through said bracket between said side flanges, a limit switch fixed to the inside of each of said side flanges and adapted to be tripped by said lever arm, a pair of springs positioned between said lever arm and said side flanges, said springs having sufficient bias to transmit a swinging movement of the lever arm to either one of said side flanges as to cause the bracket to swing, thereby rotating said shaft until a jamming action interferes with the opening or closing of the door, whereupon the bias of one of the springs is overcome as to permit said lever arm to move towards the associated side flange a sufficient degree to trip one of said limit switches; said shaft rotating means further including a reversible electric motor having an operating circuit which includes said limit switches and being fixed to the door frame on the same side of the doorway opening as said lever arm, a screw fixed to and axially aligned with the output shaft of the motor, a screw follower carried on the screw, said follower being pivotally fixed to the other end of said lever arm whereby operation of said motor causes said screw to rotate, thereby moving said follower away from 5 6 and towards the motor and carrying said other end of 2,889,875 6/1959 Turner et a1. 160188 the lever arm therewith. 2,936,830 5/1960 Mosher.

FOREIGN PATENTS 28,782 11/1921 Denmark.

References Cited UNITED STATES PATENTS 5 1 000 707 1911 Borg 1 0 1 X DAVID J. WILLIAMOWSKY, Primary Examiner.

1,947,691 2/ 1934 Baldwin et a1. 160207 X P. M. CAUN, Examiner. 

